The past decade has witnessed an intensifying focus on the development of irrigation in sub-Saharan Africa. It follows a 20-year hiatus in the wake of disappointing irrigation performance during the 1970s and 1980s. Persistent low productivity in African agriculture and vulnerability of African food supplies to increasing instability in international commodity markets are driving pan-African agricultural investment initiatives, such as the Comprehensive Africa Agricultural Development Programme (CAADP), that identify as a priority the improvement in reliability of water control for agriculture. The paper argues that, for such initiatives to be effective, there needs to be a re-appraisal of current dynamics of irrigation development in sub-Saharan Africa, particularly with respect to the role of small-scale producers' initiatives in expanding irrigation. The paper reviews the principal forms such initiatives take and argues that official narratives and statistics on African irrigation often underestimate the extent of such activities. The paper identifies five key characteristics which, it argues, contradict widely held assumptions that inform irrigation policy in Africa. The paper concludes by offering a definition of 'farmer-led irrigation' that embraces a range of interaction between producers and commercial, government and nongovernment agencies, and identifies priority areas for research on the growth potential and impact of such interactions and strategies for their future development.

This paper explores how transition management processes can be designed to address the unsustainability of water, sanitation, and hygiene (WASH) services in informal settlements in cities in Sub-Saharan Africa. The unsustainability of services related to WASH in informal settlements in Sub-Saharan Africa is deeply embedded in current societal and governance structures, cultures, and practices; it is context-dependent and involves numerous actors with different interests. Based on a literature review and empirical work in Arusha (Tanzania), Dodowa (Ghana), and Kampala (Uganda), we identify five context dimensions that account for the unsustainability of WASH services: (a) multiplicity of WASH practices, structures, and arrangements; (b) governance capacities for WASH services and maintenance; (c) landownership for sustainable access to WASH; (d) public participation in decision-making related to WASH; and (e) socio-economic inequalities governing access to WASH. These dimensions pose numerous conceptual and application challenges for transition management. Based on these challenges, recommendations are formulated for the design of a contextualized, participatory transition management process that is not only functional, but also emancipatory.

The assessment of water withdrawals for irrigation is essential for managing water resources in cultivated tropical catchments. These water withdrawals vary seasonally, driven by wet and dry seasons. A land use map is one of the required inputs of hydrological models used to estimate water withdrawals in a catchment. However, land use maps provide typically static information and do not represent the hydrological seasons and related cropping seasons and practices throughout the year. Therefore, this study assesses the value of seasonal land use maps in the quantification of water withdrawals for a tropical cultivated catchment. We developed land use maps for the main seasons (long rains, dry, and short rains) for the semi-arid Kikuletwa catchment, Tanzania. Three Landsat 8 images from 2016 were used to develop seasonal land use land cover (LULC) maps: March (long rains), August (dry season), and October (short rains). Quantitative and qualitative observation data on cropping systems (reference points and questionnaires/surveys) were collected and used for the supervised classification algorithm. Land use classifications were done using 20 land use and land cover classes for the wet season image and 19 classes for the dry and short rain season images. Water withdrawals for irrigated agriculture were calculated using (1) the static land use map or (2) the three seasonal land use maps. Clear differences in land use can be seen between the dry and the other seasons and between rain-fed and irrigated areas. A difference in water withdrawals was observed when seasonal and static land use maps were used. The highest differences were obtained for irrigated mixed crops, with an estimation of 572 million m3/year when seasonal dynamic maps were used and only 90 million m3/year when a static map was used. This study concludes that detailed seasonal land use maps are essential for quantifying annual irrigation water use of catchment areas with distinct dry and wet seasonal dynamics.

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